MLLPServer Control

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The MLLPServer control implements the server side of the Minimal Lower Layer Protocol.

Syntax

MLLPServer

Remarks

The MLLPServer control is used to exchange HL7 data with one or more connected MLLP clients.

Setting up MLLPServer to Listen for Client Connections

The first step in using the MLLPServer control is to configure it to listen for MLLP client connections. Start by setting the LocalPort property to the desired listening port. For multi-homed devices, also set the LocalHost property to the address of the network interface the MLLPServer control should listen on.

Next, optionally enable TLS/SSL with the SSLEnabled and SSLCert properties (MLLPServer supports client authentication with the SSLAuthenticateClients property).

Finally, set the Listening property to True to begin listening for client connections.

Connecting Example mllpServer.LocalHost = "localhost"; mllpServer.LocalPort = 7777; // The following two lines are only necessary if using TLS/SSL. mllpServer.SSLEnabled = true; mllpServer.SSLCert = new Certificate(CertStoreTypes.cstPFXFile, "..\\path\\to\\cert.pfx", "password", "*"); mllpServer.Listening = true;

At this point the ConnectionRequest event will fire anytime a client wishes to connect (connection requests are accepted by default), and the Connected event will fire each time a client successfully connects.

While clients are connected, the server may interact with them by using their OFTPConnectionConnectionId to interact with the control's properties.

Receiving Data

The MLLPServer control will automatically receive HL7 data sent from each client, and will automatically send acknowledgements back.

When the MLLPServer control is receiving data, immediately before data transfer begins the StartTransfer event fires. During data transfer, one or more Transfer events will fire. When data transfer is complete, the EndTransfer event fires. Any errors during data delivery will cause the Error event to fire.

Immediately before the server acknowledgement is sent the AckOut event fires. The Accept parameter of this event is used to determine the type of acknowledgement (ACK or NAK) to send back to the client.

HL7 data received by the MLLPServer control will be stored in one of the following ways:

• If an output file path has been set to the OutputFileName property, the data is written to that file.
• Otherwise, the data is stored in the OutputData property.

Sending Data

The MLLPServer control may also send data to MLLP clients. First, specify the data to send by doing one of the following:

• Set the InputFileName property to the path of a file with HL7 data.
• Set the HL7 data directly to the InputData property.

Once the data has been specified, simply call the Send method with the appropriate connection Id to send the HL7 data to the associated client. Once the client has received the data, it will respond with an acknowledgement, causing the control's AckIn event to fire.

Sending Data Example mllpServer.Connections[connectionId].InputData = "HL7Data"; mllpServer.Send(connectionId);

Property List

The following is the full list of the properties of the control with short descriptions. Click on the links for further details.

Method List

The following is the full list of the methods of the control with short descriptions. Click on the links for further details.

Event List

The following is the full list of the events fired by the control with short descriptions. Click on the links for further details.

Config Settings

The following is a list of config settings for the control with short descriptions. Click on the links for further details.

ConnectionCount Property (MLLPServer Control)

The number of records in the arrays.

Syntax

mllpservercontrol.ConnectionCount

Default Value

0

Remarks

This property controls the size of the following arrays:

• Connected
• ConnectionId
• InputData
• InputFileName
• LocalAddress
• OutputData
• OutputFileName
• RemoteHost
• RemotePort
• SSLCertEffectiveDate
• SSLCertEncoded
• SSLCertExpirationDate
• SSLCertExtendedKeyUsage
• SSLCertFingerprint
• SSLCertFingerprintSHA1
• SSLCertFingerprintSHA256
• SSLCertIssuer
• SSLCertPrivateKey
• SSLCertPrivateKeyAvailable
• SSLCertPrivateKeyContainer
• SSLCertPublicKey
• SSLCertPublicKeyAlgorithm
• SSLCertPublicKeyLength
• SSLCertSerialNumber
• SSLCertSignatureAlgorithm
• SSLCertStore
• SSLCertStorePassword
• SSLCertStoreType
• SSLCertSubject
• SSLCertSubjectAltNames
• SSLCertThumbprintMD5
• SSLCertThumbprintSHA1
• SSLCertThumbprintSHA256
• SSLCertUsage
• SSLCertUsageFlags
• SSLCertVersion
• Timeout

The array indices start at 0 and end at ConnectionCount - 1.

This property is read-only and not available at design time.

Data Type

Integer

Connected Property (MLLPServer Control)

Triggers a connection or disconnection.

Syntax

mllpservercontrol.Connected(ConnectionId)

Default Value

False

Remarks

Triggers a connection or disconnection.

This property triggers a connection or disconnection.

Setting this property to True initiates a connection attempt to the host specified by the RemoteHost property. If successful, the value of this property changes to True and the Connected event is fired.

The ConnectionId parameter specifies the index of the item in the array. The size of the array is controlled by the ConnectionCount property.

This property is read-only and not available at design time.

Data Type

Boolean

ConnectionId Property (MLLPServer Control)

The Id of the connection.

Syntax

mllpservercontrol.ConnectionId(ConnectionId)

Default Value

0

Remarks

The Id of the connection.

This property contains an identifier generated by the control that uniquely identifies the connection.

The ConnectionId parameter specifies the index of the item in the array. The size of the array is controlled by the ConnectionCount property.

This property is read-only and not available at design time.

Data Type

Integer

InputData Property (MLLPServer Control)

The raw HL7 data to send.

Syntax

mllpservercontrol.InputData(ConnectionId)[=string]

Default Value

""

Remarks

The raw HL7 data to send.

This property is used to specify the HL7 data to send when the Send method is called.

Note that the control checks the following places for input data, in order, when Send is called. Input data is sent from the first place it is found:

• The contents of a file whose path has been set to the connection's InputFileName property.
• The data set to the connection's InputData property.

The ConnectionId parameter specifies the index of the item in the array. The size of the array is controlled by the ConnectionCount property.

To read or write binary data to the property, a Variant (Byte Array) version is provided in .InputDataB.

This property is not available at design time.

Data Type

Binary String

InputFileName Property (MLLPServer Control)

The path of a file containing HL7 data to send.

Syntax

mllpservercontrol.InputFileName(ConnectionId)[=string]

Default Value

""

Remarks

The path of a file containing HL7 data to send.

This property is used to specify a path to a file whose contents will be sent when the Send method is called.

Note that the control checks the following places for input data, in order, when Send is called. Input data is sent from the first place it is found:

• The contents of a file whose path has been set to the connection's InputFileName property.
• The data set to the connection's InputData property.

The ConnectionId parameter specifies the index of the item in the array. The size of the array is controlled by the ConnectionCount property.

This property is not available at design time.

Data Type

String

LocalAddress Property (MLLPServer Control)

The address of the local interface through which the connection is passing.

Syntax

mllpservercontrol.LocalAddress(ConnectionId)

Default Value

""

Remarks

The address of the local interface through which the connection is passing.

This property reflects the address of the local network interface through which the connection is passing. This information is typically only important for multi-homed devices.

The ConnectionId parameter specifies the index of the item in the array. The size of the array is controlled by the ConnectionCount property.

This property is read-only and not available at design time.

Data Type

String

OutputData Property (MLLPServer Control)

The raw HL7 data received.

Syntax

mllpservercontrol.OutputData(ConnectionId)

Default Value

""

Remarks

The raw HL7 data received.

This property holds the raw HL7 data received from the MLLP client.

Note that the control will store output data in one of the following places, choosing the first one that is valid:

• A file whose path has been set to the connection's OutputFileName property.
• The connection's OutputData property.

The ConnectionId parameter specifies the index of the item in the array. The size of the array is controlled by the ConnectionCount property.

To read or write binary data to the property, a Variant (Byte Array) version is provided in .OutputDataB.

This property is read-only and not available at design time.

Data Type

Binary String

OutputFileName Property (MLLPServer Control)

The path of a file in which to store received HL7 data.

Syntax

mllpservercontrol.OutputFileName(ConnectionId)[=string]

Default Value

""

Remarks

The path of a file in which to store received HL7 data.

This property is used to specify a path to a file in which to store HL7 data received from the MLLP client.

Note that the control will store output data in one of the following places, choosing the first one that is valid:

• A file whose path has been set to the connection's OutputFileName property.
• The connection's OutputData property.

The ConnectionId parameter specifies the index of the item in the array. The size of the array is controlled by the ConnectionCount property.

This property is not available at design time.

Data Type

String

RemoteHost Property (MLLPServer Control)

The address of the MLLP client associated with the connection.

Syntax

mllpservercontrol.RemoteHost(ConnectionId)

Default Value

""

Remarks

The address of the MLLP client associated with the connection.

This property reflects the address of the MLLP client associated with the connection.

The ConnectionId parameter specifies the index of the item in the array. The size of the array is controlled by the ConnectionCount property.

This property is read-only and not available at design time.

Data Type

String

RemotePort Property (MLLPServer Control)

The port of the MLLP client associated with the connection.

Syntax

mllpservercontrol.RemotePort(ConnectionId)

Default Value

0

Remarks

The port of the MLLP client associated with the connection.

This property reflects the port of the MLLP client associated with the connection.

The ConnectionId parameter specifies the index of the item in the array. The size of the array is controlled by the ConnectionCount property.

This property is read-only and not available at design time.

Data Type

Integer

Timeout Property (MLLPServer Control)

The timeout value, in seconds, for the connection.

Syntax

mllpservercontrol.Timeout(ConnectionId)[=integer]

Default Value

0

Remarks

The timeout value, in seconds, for the connection.

This property specifies the timeout, in seconds, to use for the connection.

If set to 0, all operations return immediately, potentially failing with a WOULDBLOCK error if data can't be sent immediately.

If set to a positive value, the control will automatically retry each operation that would otherwise result in a WOULDBLOCK error for a maximum of Timeout seconds.

The control will use DoEvents to enter an efficient wait loop during any potential waiting period, making sure that all system events are processed immediately as they arrive. This ensures that the host application does not freeze and remains responsive.

If Timeout expires, and the operation is not yet complete, the control fails with an error.

Note: By default, all timeouts are inactivity timeouts, that is, the timeout period is extended by Timeout seconds when any amount of data is successfully sent or received.

The default value is 0 (asynchronous operation).

The ConnectionId parameter specifies the index of the item in the array. The size of the array is controlled by the ConnectionCount property.

This property is not available at design time.

Data Type

Integer

DefaultTimeout Property (MLLPServer Control)

This property includes an initial timeout value to be used by incoming connections.

Syntax

mllpservercontrol.DefaultTimeout[=integer]

Default Value

0

Remarks

This property is used by the control to set the operational timeout value of all inbound connections once they are established.

By default, the timeout is 0, meaning that all inbound connections will behave asynchronously.

Data Type

Integer

KeepAlive Property (MLLPServer Control)

When True, KEEPALIVE packets are enabled (for long connections).

Syntax

mllpservercontrol.KeepAlive[=boolean]

Default Value

False

Remarks

This property enables the SO_KEEPALIVE option on the incoming connections. This option prevents long connections from timing out in case of inactivity.

Note: System Transmission Control Protocol (TCP)/IP stack implementations are not required to support SO_KEEPALIVE.

This property is shared among incoming connections. When the property is set, the corresponding value is set for incoming connections as they are accepted. Existing connections are not modified.

Data Type

Boolean

Listening Property (MLLPServer Control)

This property indicates whether the control is listening for incoming connections on LocalPort.

Syntax

mllpservercontrol.Listening

Default Value

False

Remarks

This property indicates whether the control is listening for connections on the port specified by the LocalPort property. Use the StartListening and StopListening methods to control whether the control is listening.

This property is read-only and not available at design time.

Data Type

Boolean

LocalHost Property (MLLPServer Control)

The name of the local host or user-assigned IP interface through which connections are initiated or accepted.

Syntax

mllpservercontrol.LocalHost[=string]

Default Value

""

Remarks

This property contains the name of the local host as obtained by the gethostname() system call, or if the user has assigned an IP address, the value of that address.

In multihomed hosts (machines with more than one IP interface) setting LocalHost to the IP address of an interface will make the control initiate connections (or accept in the case of server controls) only through that interface. It is recommended to provide an IP address rather than a hostname when setting this property to ensure the desired interface is used.

If the control is connected, the LocalHost property shows the IP address of the interface through which the connection is made in internet dotted format (aaa.bbb.ccc.ddd). In most cases, this is the address of the local host, except for multihomed hosts (machines with more than one IP interface).

Note: LocalHost is not persistent. You must always set it in code, and never in the property window.

Data Type

String

LocalPort Property (MLLPServer Control)

This property includes the Transmission Control Protocol (TCP) port in the local host where the control listens.

Syntax

mllpservercontrol.LocalPort[=integer]

Default Value

0

Remarks

This property must be set before the control can start listening. If its value is 0, then the TCP/IP subsystem picks a port number at random. The port number can be found by checking the value of this property after the control is listening (i.e., after successfully assigning True to the Listening property).

The service port is not shared among servers so two controls cannot be listening on the same port at the same time.

Data Type

Integer

SSLAuthenticateClients Property (MLLPServer Control)

If set to True, the server asks the client(s) for a certificate.

Syntax

mllpservercontrol.SSLAuthenticateClients[=boolean]

Default Value

False

Remarks

This property is used in conjunction with the SSLClientAuthentication event. Please refer to the documentation of the SSLClientAuthentication event for details.

Data Type

Boolean

SSLCertEffectiveDate Property (MLLPServer Control)

The date on which this certificate becomes valid.

Syntax

mllpservercontrol.SSLCertEffectiveDate

Default Value

""

Remarks

The date on which this certificate becomes valid. Before this date, it is not valid. The date is localized to the system's time zone. The following example illustrates the format of an encoded date:

23-Jan-2000 15:00:00.

This property is read-only.

Data Type

String

SSLCertExpirationDate Property (MLLPServer Control)

The date on which the certificate expires.

Syntax

mllpservercontrol.SSLCertExpirationDate

Default Value

""

Remarks

The date on which the certificate expires. After this date, the certificate will no longer be valid. The date is localized to the system's time zone. The following example illustrates the format of an encoded date:

23-Jan-2001 15:00:00.

This property is read-only.

Data Type

String

SSLCertExtendedKeyUsage Property (MLLPServer Control)

A comma-delimited list of extended key usage identifiers.

Syntax

mllpservercontrol.SSLCertExtendedKeyUsage

Default Value

""

Remarks

A comma-delimited list of extended key usage identifiers. These are the same as ASN.1 object identifiers (OIDs).

This property is read-only.

Data Type

String

SSLCertFingerprint Property (MLLPServer Control)

The hex-encoded, 16-byte MD5 fingerprint of the certificate.

Syntax

mllpservercontrol.SSLCertFingerprint

Default Value

""

Remarks

The hex-encoded, 16-byte MD5 fingerprint of the certificate. This property is primarily used for keys which do not have a corresponding X.509 public certificate, such as PEM keys that only contain a private key. It is commonly used for SSH keys.

The following example illustrates the format: bc:2a:72:af:fe:58:17:43:7a:5f:ba:5a:7c:90:f7:02

This property is read-only.

Data Type

String

SSLCertFingerprintSHA1 Property (MLLPServer Control)

The hex-encoded, 20-byte SHA-1 fingerprint of the certificate.

Syntax

mllpservercontrol.SSLCertFingerprintSHA1

Default Value

""

Remarks

The hex-encoded, 20-byte SHA-1 fingerprint of the certificate. This property is primarily used for keys which do not have a corresponding X.509 public certificate, such as PEM keys that only contain a private key. It is commonly used for SSH keys.

The following example illustrates the format: 30:7b:fa:38:65:83:ff:da:b4:4e:07:3f:17:b8:a4:ed:80:be:ff:84

This property is read-only.

Data Type

String

SSLCertFingerprintSHA256 Property (MLLPServer Control)

The hex-encoded, 32-byte SHA-256 fingerprint of the certificate.

Syntax

mllpservercontrol.SSLCertFingerprintSHA256

Default Value

""

Remarks

The hex-encoded, 32-byte SHA-256 fingerprint of the certificate. This property is primarily used for keys which do not have a corresponding X.509 public certificate, such as PEM keys that only contain a private key. It is commonly used for SSH keys.

The following example illustrates the format: 6a:80:5c:33:a9:43:ea:b0:96:12:8a:64:96:30:ef:4a:8a:96:86:ce:f4:c7:be:10:24:8e:2b:60:9e:f3:59:53

This property is read-only.

Data Type

String

SSLCertIssuer Property (MLLPServer Control)

The issuer of the certificate.

Syntax

mllpservercontrol.SSLCertIssuer

Default Value

""

Remarks

The issuer of the certificate. This property contains a string representation of the name of the issuing authority for the certificate.

This property is read-only.

Data Type

String

SSLCertPrivateKey Property (MLLPServer Control)

The private key of the certificate (if available).

Syntax

mllpservercontrol.SSLCertPrivateKey

Default Value

""

Remarks

The private key of the certificate (if available). The key is provided as PEM/Base64-encoded data.

Note: The PrivateKey may be available but not exportable. In this case, PrivateKey returns an empty string.

This property is read-only.

Data Type

String

SSLCertPrivateKeyAvailable Property (MLLPServer Control)

Whether a PrivateKey is available for the selected certificate.

Syntax

mllpservercontrol.SSLCertPrivateKeyAvailable

Default Value

False

Remarks

Whether a PrivateKey is available for the selected certificate. If PrivateKeyAvailable is True, the certificate may be used for authentication purposes (e.g., server authentication).

This property is read-only.

Data Type

Boolean

SSLCertPrivateKeyContainer Property (MLLPServer Control)

The name of the PrivateKey container for the certificate (if available).

Syntax

mllpservercontrol.SSLCertPrivateKeyContainer

Default Value

""

Remarks

The name of the PrivateKey container for the certificate (if available). This functionality is available only on Windows platforms.

This property is read-only.

Data Type

String

SSLCertPublicKey Property (MLLPServer Control)

The public key of the certificate.

Syntax

mllpservercontrol.SSLCertPublicKey

Default Value

""

Remarks

The public key of the certificate. The key is provided as PEM/Base64-encoded data.

This property is read-only.

Data Type

String

SSLCertPublicKeyAlgorithm Property (MLLPServer Control)

The textual description of the certificate's public key algorithm.

Syntax

mllpservercontrol.SSLCertPublicKeyAlgorithm

Default Value

""

Remarks

The textual description of the certificate's public key algorithm. The property contains either the name of the algorithm (e.g., "RSA" or "RSA_DH") or an object identifier (OID) string representing the algorithm.

This property is read-only.

Data Type

String

SSLCertPublicKeyLength Property (MLLPServer Control)

The length of the certificate's public key (in bits).

Syntax

mllpservercontrol.SSLCertPublicKeyLength

Default Value

0

Remarks

The length of the certificate's public key (in bits). Common values are 512, 1024, and 2048.

This property is read-only.

Data Type

Integer

SSLCertSerialNumber Property (MLLPServer Control)

The serial number of the certificate encoded as a string.

Syntax

mllpservercontrol.SSLCertSerialNumber

Default Value

""

Remarks

The serial number of the certificate encoded as a string. The number is encoded as a series of hexadecimal digits, with each pair representing a byte of the serial number.

This property is read-only.

Data Type

String

SSLCertSignatureAlgorithm Property (MLLPServer Control)

The text description of the certificate's signature algorithm.

Syntax

mllpservercontrol.SSLCertSignatureAlgorithm

Default Value

""

Remarks

The text description of the certificate's signature algorithm. The property contains either the name of the algorithm (e.g., "RSA" or "RSA_MD5RSA") or an object identifier (OID) string representing the algorithm.

This property is read-only.

Data Type

String

SSLCertStore Property (MLLPServer Control)

The name of the certificate store for the client certificate.

Syntax

mllpservercontrol.SSLCertStore[=string]

Default Value

"MY"

Remarks

The name of the certificate store for the client certificate.

The StoreType property denotes the type of the certificate store specified by Store. If the store is password-protected, specify the password in StorePassword.

Store is used in conjunction with the Subject property to specify client certificates. If Store has a value, and Subject or Encoded is set, a search for a certificate is initiated. Please see the Subject property for details.

Designations of certificate stores are platform dependent.

The following designations are the most common User and Machine certificate stores in Windows:

When the certificate store type is cstPFXFile, this property must be set to the name of the file. When the type is cstPFXBlob, the property must be set to the binary contents of a PFX file (i.e., PKCS#12 certificate store).

To read or write binary data to the property, a Variant (Byte Array) version is provided in .SSLCertStoreB.

Data Type

Binary String

SSLCertStorePassword Property (MLLPServer Control)

If the type of certificate store requires a password, this property is used to specify the password needed to open the certificate store.

Syntax

mllpservercontrol.SSLCertStorePassword[=string]

Default Value

""

Remarks

If the type of certificate store requires a password, this property is used to specify the password needed to open the certificate store.

Data Type

String

SSLCertStoreType Property (MLLPServer Control)

The type of certificate store for this certificate.

Syntax

mllpservercontrol.SSLCertStoreType[=integer]

Possible Values

cstUser(0), 
cstMachine(1), 
cstPFXFile(2), 
cstPFXBlob(3), 
cstJKSFile(4), 
cstJKSBlob(5), 
cstPEMKeyFile(6), 
cstPEMKeyBlob(7), 
cstPublicKeyFile(8), 
cstPublicKeyBlob(9), 
cstSSHPublicKeyBlob(10), 
cstP7BFile(11), 
cstP7BBlob(12), 
cstSSHPublicKeyFile(13), 
cstPPKFile(14), 
cstPPKBlob(15), 
cstXMLFile(16), 
cstXMLBlob(17), 
cstJWKFile(18), 
cstJWKBlob(19), 
cstSecurityKey(20), 
cstBCFKSFile(21), 
cstBCFKSBlob(22), 
cstPKCS11(23), 
cstAuto(99)

Default Value

0

Remarks

The type of certificate store for this certificate.

The control supports both public and private keys in a variety of formats. When the cstAuto value is used, the control will automatically determine the type. This property can take one of the following values:

Data Type

Integer

SSLCertSubjectAltNames Property (MLLPServer Control)

Comma-separated lists of alternative subject names for the certificate.

Syntax

mllpservercontrol.SSLCertSubjectAltNames

Default Value

""

Remarks

Comma-separated lists of alternative subject names for the certificate.

This property is read-only.

Data Type

String

SSLCertThumbprintMD5 Property (MLLPServer Control)

The MD5 hash of the certificate.

Syntax

mllpservercontrol.SSLCertThumbprintMD5

Default Value

""

Remarks

The MD5 hash of the certificate. It is primarily used for X.509 certificates. If the hash does not already exist, it is automatically computed.

This property is read-only.

Data Type

String

SSLCertThumbprintSHA1 Property (MLLPServer Control)

The SHA-1 hash of the certificate.

Syntax

mllpservercontrol.SSLCertThumbprintSHA1

Default Value

""

Remarks

The SHA-1 hash of the certificate. It is primarily used for X.509 certificates. If the hash does not already exist, it is automatically computed.

This property is read-only.

Data Type

String

SSLCertThumbprintSHA256 Property (MLLPServer Control)

The SHA-256 hash of the certificate.

Syntax

mllpservercontrol.SSLCertThumbprintSHA256

Default Value

""

Remarks

The SHA-256 hash of the certificate. It is primarily used for X.509 certificates. If the hash does not already exist, it is automatically computed.

This property is read-only.

Data Type

String

SSLCertUsage Property (MLLPServer Control)

The text description of UsageFlags .

Syntax

mllpservercontrol.SSLCertUsage

Default Value

""

Remarks

The text description of UsageFlags.

This value will be one or more of the following strings and will be separated by commas:

• Digital Signature
• Non-Repudiation
• Key Encipherment
• Data Encipherment
• Key Agreement
• Certificate Signing
• CRL Signing
• Encipher Only

If the provider is OpenSSL, the value is a comma-separated list of X.509 certificate extension names.

This property is read-only.

Data Type

String

SSLCertUsageFlags Property (MLLPServer Control)

The flags that show intended use for the certificate.

Syntax

mllpservercontrol.SSLCertUsageFlags

Default Value

0

Remarks

The flags that show intended use for the certificate. The value of UsageFlags is a combination of the following flags:

Please see the Usage property for a text representation of UsageFlags.

This functionality currently is not available when the provider is OpenSSL.

This property is read-only.

Data Type

Integer

SSLCertVersion Property (MLLPServer Control)

The certificate's version number.

Syntax

mllpservercontrol.SSLCertVersion

Default Value

""

Remarks

The certificate's version number. The possible values are the strings "V1", "V2", and "V3".

This property is read-only.

Data Type

String

SSLCertSubject Property (MLLPServer Control)

The subject of the certificate used for client authentication.

Syntax

mllpservercontrol.SSLCertSubject[=string]

Default Value

""

Remarks

The subject of the certificate used for client authentication.

This property must be set after all other certificate properties are set. When this property is set, a search is performed in the current certificate store to locate a certificate with a matching subject.

If a matching certificate is found, the property is set to the full subject of the matching certificate.

If an exact match is not found, the store is searched for subjects containing the value of the property.

If a match is still not found, the property is set to an empty string, and no certificate is selected.

The special value "*" picks a random certificate in the certificate store.

The certificate subject is a comma-separated list of distinguished name fields and values. For instance, "CN=www.server.com, OU=test, C=US, E=support@nsoftware.com". Common fields and their meanings are as follows:

If a field value contains a comma, it must be quoted.

Data Type

String

SSLCertEncoded Property (MLLPServer Control)

The certificate (PEM/Base64 encoded).

Syntax

mllpservercontrol.SSLCertEncoded[=string]

Default Value

""

Remarks

The certificate (PEM/Base64 encoded). This property is used to assign a specific certificate. The Store and Subject properties also may be used to specify a certificate.

When Encoded is set, a search is initiated in the current Store for the private key of the certificate. If the key is found, Subject is updated to reflect the full subject of the selected certificate; otherwise, Subject is set to an empty string.

To read or write binary data to the property, a Variant (Byte Array) version is provided in .SSLCertEncodedB.

This property is not available at design time.

Data Type

Binary String

SSLEnabled Property (MLLPServer Control)

This property indicates whether Transport Layer Security/Secure Sockets Layer (TLS/SSL) is enabled.

Syntax

mllpservercontrol.SSLEnabled[=boolean]

Default Value

False

Remarks

This property specifies whether TLS/SSL is enabled in the control. When False (default), the control operates in plaintext mode. When True, TLS/SSL is enabled.

TLS/SSL may also be enabled by setting SSLStartMode. Setting SSLStartMode will automatically update this property value.

This property is not available at design time.

Data Type

Boolean

Version Property (MLLPServer Control)

The MLLP version to use.

Syntax

mllpservercontrol.Version[=integer]

Possible Values

mvVersion1(1), 
mvVersion2(2)

Default Value

2

Remarks

This property specifies the MLLP version the control should use. Valid values are:

• mvVersion1 (1) - MLLP Version 1
• mvVersion2 (2) - MLLP Version 2 (default)

When using MLLP version 1, there are no acknowledgements, so the AckIn and AckOut events will never fire.

This property is not available at design time.

Data Type

Integer

Config Method (MLLPServer Control)

Sets or retrieves a configuration setting.

Syntax

mllpservercontrol.Config ConfigurationString

Remarks

Config is a generic method available in every control. It is used to set and retrieve configuration settings for the control.

These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the control, access to these internal properties is provided through the Config method.

To set a configuration setting named PROPERTY, you must call Config("PROPERTY=VALUE"), where VALUE is the value of the setting expressed as a string. For boolean values, use the strings "True", "False", "0", "1", "Yes", or "No" (case does not matter).

To read (query) the value of a configuration setting, you must call Config("PROPERTY"). The value will be returned as a string.

Disconnect Method (MLLPServer Control)

This method disconnects the specified client.

Syntax

mllpservercontrol.Disconnect ConnectionId

Remarks

Calling this method will disconnect the client specified by the ConnectionId parameter.

DoEvents Method (MLLPServer Control)

This method processes events from the internal message queue.

Syntax

mllpservercontrol.DoEvents 

Remarks

When DoEvents is called, the control processes any available events. If no events are available, it waits for a preset period of time, and then returns.

Interrupt Method (MLLPServer Control)

This method interrupts a synchronous send to the remote host.

Syntax

mllpservercontrol.Interrupt ConnectionId

Remarks

This property is called using the Connection Id if you wish to interrupt a connection and stop a file from uploading without disconnecting the client connected to the control. If you use SendFile to upload a file, the control will run synchronously on that Connection Id until it is completed.

Reset Method (MLLPServer Control)

This method will reset the control.

Syntax

mllpservercontrol.Reset 

Remarks

This method will reset the control's properties to their default values.

Send Method (MLLPServer Control)

Send HL7 data to the MLLP client associated with the specified connection Id.

Syntax

mllpservercontrol.Send ConnectionId

Remarks

The Send method sends data for the connection specified by ConnectionId to the associated MLLP client.

Before calling this method, specify the data to send by doing one of the following (the control will use the data from the first valid location):

• Set the InputFileName property to the path of a file with HL7 data.
• Set the HL7 data directly to the InputData property.

ConnectionId is the connected client to which the server should Send.

Once the client has received the data, it will respond with an acknowledgement, causing the control's AckIn event to fire.

Sending Data Example mllpServer.Connections[connectionId].InputData = "HL7Data"; mllpServer.Send(connectionId);

Shutdown Method (MLLPServer Control)

This method shuts down the server.

Syntax

mllpservercontrol.Shutdown 

Remarks

This method shuts down the server. Calling this method is equivalent to calling StopListening and then breaking every client connection by calling Disconnect.

StartListening Method (MLLPServer Control)

This method starts listening for incoming connections.

Syntax

mllpservercontrol.StartListening 

Remarks

This method begins listening for incoming connections on the port specified by LocalPort. Once listening, events will fire as new clients connect and data are transferred.

To stop listening for new connections, call StopListening. To stop listening for new connections and to disconnect all existing clients, call Shutdown.

StopListening Method (MLLPServer Control)

This method stops listening for new connections.

Syntax

mllpservercontrol.StopListening 

Remarks

This method stops listening for new connections. After being called, any new connection attempts will be rejected. Calling this method does not disconnect existing connections.

To stop listening and to disconnect all existing clients, call Shutdown instead.

AckIn Event (MLLPServer Control)

Fires immediately after receiving an acknowledgement from a client.

Syntax

Sub mllpservercontrol_AckIn(ConnectionId As Integer, Accepted As Boolean)

Remarks

This event fires immediately after receiving an acknowledgement (positive or negative) from an MLLP client.

The ConnectionId parameter reflects the Id of the connection that the acknowledgement was received on.

The Accepted parameter reflects whether the acknowledgement is positive (ACK - True) or negative (NAK - False).

Anytime a negative acknowledgement is received, the control will report an error with code 670.

AckOut Event (MLLPServer Control)

Fires immediately before sending an acknowledgement to a client.

Syntax

Sub mllpservercontrol_AckOut(ConnectionId As Integer, Accept As Boolean)

Remarks

This event fires immediately before the control sends an acknowledgement to an MLLP client.

ConnectionId is the Id of the connection that will receive the acknowledgement.

The Accept parameter should be set to indicate whether the control should send a positive (ACK - True) or negative (NAK - False) acknowledgement. The default is True.

Connected Event (MLLPServer Control)

This event is fired immediately after a connection completes (or fails).

Syntax

Sub mllpservercontrol_Connected(ConnectionId As Integer, StatusCode As Integer, Description As String)

Remarks

If the connection is made normally, StatusCode is 0, and Description is "OK".

If the connection fails, StatusCode has the error code returned by the system. Description contains a description of this code. The value of StatusCode is equal to the value of the system error. The corresponding Visual Basic error code can be obtained by adding 15001 to this value.

Please refer to the Error Codes section for more information.

ConnectionRequest Event (MLLPServer Control)

This event is fired when a request for connection comes from a remote host.

Syntax

Sub mllpservercontrol_ConnectionRequest(Address As String, Port As Integer, Accept As Boolean)

Remarks

This event indicates an incoming connection. The connection is accepted by default. Address and Port will contain information about the remote host requesting the inbound connection. If you want to refuse it, you can set the Accept parameter to False.

Disconnected Event (MLLPServer Control)

This event is fired when a connection is closed.

Syntax

Sub mllpservercontrol_Disconnected(ConnectionId As Integer, StatusCode As Integer, Description As String)

Remarks

If the connection is broken normally, StatusCode is 0, and Description is "OK".

If the connection is broken for any other reason, StatusCode has the error code returned by the system. Description contains a description of this code. The value of StatusCode is equal to the value of the system error. The corresponding Visual Basic error code can be obtained by adding 15001 to this value.

Please refer to the Error Codes section for more information.

EndTransfer Event (MLLPServer Control)

Fires after incoming HL7 data finishes transferring.

Syntax

Sub mllpservercontrol_EndTransfer(ConnectionId As Integer)

Remarks

This event fires after incoming HL7 data finishes transferring, immediately before the AckOut event is fired.

ConnectionId is the Id of the connection on which the data was received.

Error Event (MLLPServer Control)

This event fires information about errors during data delivery.

Syntax

Sub mllpservercontrol_Error(ConnectionId As Integer, ErrorCode As Integer, Description As String)

Remarks

The Error event is fired in case of exceptional conditions during message processing. Normally, the control fails with an error.

ErrorCode contains an error code and Description contains a textual description of the error. For a list of valid error codes and their descriptions, please refer to the Error Codes section.

ConnectionId indicates the connection for which the error is applicable.

Log Event (MLLPServer Control)

Provides logging information.

Syntax

Sub mllpservercontrol_Log(ConnectionId As Integer, LogLevel As Integer, Message As String, LogType As String)

Remarks

This event fires when processing messages and provides logging information. The LogLevel configuration setting specifies the level of detail that is logged.

ConnectionId reflects the Id of the connection to which the log message pertains.

LogType specifies the type of log message. Possible values are:

• INFO
• VERBOSE
• DEBUG

LogMessage is the log message.

SSLClientAuthentication Event (MLLPServer Control)

This event is fired when the client presents its credentials to the server.

Syntax

Sub mllpservercontrol_SSLClientAuthentication(ConnectionId As Integer, CertEncoded As String, CertSubject As String, CertIssuer As String, Status As String, Accept As Boolean)

Remarks

This event enables the server to decide whether or not to continue. The Accept parameter is a recommendation on whether to continue or to close the connection. This is just a suggestion: application software must use its own logic to determine whether or not to continue.

When Accept is False, Status shows why the verification failed (otherwise, Status contains the string "OK").

SSLConnectionRequest Event (MLLPServer Control)

This event fires when a Secure Sockets Layer (SSL) connection is requested.

Syntax

Sub mllpservercontrol_SSLConnectionRequest(ConnectionId As Integer, SupportedCipherSuites As String, SupportedSignatureAlgs As String, CertStoreType As Integer, CertStore As String, CertPassword As String, CertSubject As String)

Remarks

This event fires when an SSL connection is requested and SSLProvider is set to Internal. This event provides an opportunity to select an alternative certificate to the connecting client. This event does not fire when SSLProvider is set to Platform.

This event allows the control to be configured to use both RSA and ECDSA certificates depending on the connecting client's capabilities.

ConnectionId is the connection Id of the client requesting the connection.

SupportedCipherSuites is a comma-separated list of cipher suites that the client supports.

SupportedSignatureAlgs is a comma-separated list of certificate signature algorithms that the client supports.

CertStoreType is the store type of the alternate certificate to use for this connection. The control supports both public and private keys in a variety of formats. When the cstAuto value is used, the control will automatically determine the type. This property can take one of the following values:

CertStore is the store name or location of the alternate certificate to use for this connection.

Designations of certificate stores are platform dependent.

The following designations are the most common User and Machine certificate stores in Windows:

When the certificate store type is cstPFXFile, this property must be set to the name of the file. When the type is cstPFXBlob, the property must be set to the binary contents of a PFX file (i.e., PKCS#12 certificate store).

CertPassword is the password of the certificate store containing the alternate certificate to use for this connection.

CertSubject is the subject of the alternate certificate to use for this connection.

The special value * matches any subject and will select the first certificate in the store. The certificate subject is a comma-separated list of distinguished name fields and values. For instance, "CN=www.server.com, OU=test, C=US, E=support@nsoftware.com". Common fields and their meanings are as follows:

If a field value contains a comma, it must be quoted.

SSLStatus Event (MLLPServer Control)

This event is fired to show the progress of the secure connection.

Syntax

Sub mllpservercontrol_SSLStatus(ConnectionId As Integer, Message As String)

Remarks

The event is fired for informational and logging purposes only. It is used to track the progress of the connection.

StartTransfer Event (MLLPServer Control)

Fires before incoming HL7 data begins transferring.

Syntax

Sub mllpservercontrol_StartTransfer(ConnectionId As Integer)

Remarks

This event fires before incoming HL7 data begins transferring.

ConnectionId is the Id of the connection on which data is being received.

Transfer Event (MLLPServer Control)

Fires during incoming data transfer.

Syntax

Sub mllpservercontrol_Transfer(ConnectionId As Integer, BytesTransferred As Long64, data As String)

Remarks

This event fires one or more times while incoming data is being transferred.

The ConnectionId parameter is the Id of the connection on which data is being transferred.

The BytesTransferred parameter reflects the number of bytes transferred since the beginning of the transfer.

The Data parameter contains the portion of the data being delivered currently.

Config Settings (MLLPServer Control)

MLLPServer Config Settings

TCPClient Config Settings

SSL Config Settings

-----BEGIN CERTIFICATE-----
MIIEKzCCAxOgAwIBAgIRANTET4LIkxdH6P+CFIiHvTowDQYJKoZIhvcNAQELBQAw
... Intermediate Cert ...
eWHV5OW1K53o/atv59sOiW5K3crjFhsBOd5Q+cJJnU+SWinPKtANXMht+EDvYY2w
F0I1XhM+pKj7FjDr+XNj
-----END CERTIFICATE-----
\r \n
-----BEGIN CERTIFICATE-----
MIIEFjCCAv6gAwIBAgIQetu1SMxpnENAnnOz1P+PtTANBgkqhkiG9w0BAQUFADBp
... Root Cert ...
d8q23djXZbVYiIfE9ebr4g3152BlVCHZ2GyPdjhIuLeH21VbT/dyEHHA
-----END CERTIFICATE-----

-----BEGIN CERTIFICATE-----
MIIEKzCCAxOgAwIBAgIRANTET4LIkxdH6P+CFIiHvTowDQYJKoZIhvcNAQELBQAw
... Intermediate Cert ...
eWHV5OW1K53o/atv59sOiW5K3crjFhsBOd5Q+cJJnU+SWinPKtANXMht+EDvYY2w
F0I1XhM+pKj7FjDr+XNj
-----END CERTIFICATE-----
\r \n
-----BEGIN CERTIFICATE-----
MIIEFjCCAv6gAwIBAgIQetu1SMxpnENAnnOz1P+PtTANBgkqhkiG9w0BAQUFADBp
... Root Cert ...
d8q23djXZbVYiIfE9ebr4g3152BlVCHZ2GyPdjhIuLeH21VbT/dyEHHA
-----END CERTIFICATE-----

-----BEGIN CERTIFICATE-----
MIIEKzCCAxOgAwIBAgIRANTET4LIkxdH6P+CFIiHvTowDQYJKoZIhvcNAQELBQAw
... Intermediate Cert...
eWHV5OW1K53o/atv59sOiW5K3crjFhsBOd5Q+cJJnU+SWinPKtANXMht+EDvYY2w
F0I1XhM+pKj7FjDr+XNj
-----END CERTIFICATE-----
\r \n
-----BEGIN CERTIFICATE-----
MIIEFjCCAv6gAwIBAgIQetu1SMxpnENAnnOz1P+PtTANBgkqhkiG9w0BAQUFADBp
... Root Cert...
d8q23djXZbVYiIfE9ebr4g3152BlVCHZ2GyPdjhIuLeH21VbT/dyEHHA
-----END CERTIFICATE-----

Socket Config Settings

Base Config Settings

Trappable Errors (MLLPServer Control)

MLLPServer Errors

TCPClient Errors

TCP/IP Errors